基于RGD多肽掺杂聚吡咯-铟锡氧化物的仿生微电极构建及用于细胞生物学行为的电化学阻抗谱检测

构建一种基于RGD多肽分子掺杂聚吡咯膜修饰的铟锡氧化物微电极(PPy/RGD-ITO),并以此作为传感电极实现细胞生物学行为的电化学阻抗谱检测.采用光刻技术蚀刻感光干膜绝缘层制备ITO微电极;以含RGD模体的多肽分子作为吡咯电聚合唯一的掺杂阴离子,通过电化学共聚合方式在ITO微电极表面沉积PPy/RGD复合膜形成PPy/RGD-ITO微电极;原子力显微镜(AFM)、接触角测量仪和傅里叶变换红外光谱仪(FTIR)分别表征PPy/RGD复合膜的表面拓扑形貌、湿润性和组成成分;人肺癌细胞株A549铺展、粘附及增殖实验考察了PPy/RGD复合膜与细胞间的相互作用;以构建的PPy/RGD-ITO微电极作为传感电极,通过电化学阻抗谱技术对A549细胞粘附增殖行为及天然抗癌药物分子重楼皂苷I的细胞毒性进行了分析.结果显示,通过简单的电化学共聚合成功将RGD分子掺杂进PPy膜内,且PPy/RGD复合膜具有优异的表面物理性能;PPy基质膜内掺杂的RGD分子保留其生物活性,相比裸ITO电极和聚4-苯乙烯磺酸钠(PSS)掺杂的PPy膜,PPy/RGD复合膜能更好地促进A549细胞的铺展、粘附和增殖;由于PPy/RGD-ITO微电极表面A549细胞形态学变化可改变电极系统的阻抗谱特征,因此通过电化学阻抗谱技术可解析A549细胞粘附增殖行为学信息,同时可定量分析重楼皂苷I细胞毒性.因此,通过简单的电化学共聚合方法将生物活性RGD分子掺杂进PPy膜内制备出的PPy/RGD膜具有优良的生物相容性,可作为一种重要的仿生电极修饰材料用于构建电子系统和细胞生物学系统的耦合界面,未来可应用于细胞生物学行为及药物筛选研究.

Construction of a Biomimetic Microelectrode Based on RGD Peptide/Polypyrrole- Indium Tin Oxide for Detecting Cell Biology Behaviors by Electrochemical Impedance Spectroscopy

For fabricating an indium tin oxide(ITO)microelectrode modified with RGD peptide doped polypyrrole(PPy/RGD-ITO)and using it as sensing electrode for detecting cell biology behaviors by electrochemical impedance spectroscopy.The ITO microelectrode was firstly fabricated by etching the insulating layer of photosensitive dry film with lithography technology.Then the PPy/RGD composite was deposited on the surface of the ITO microelectrode by electrochemical copolymerization using the peptide contained RGD motif as the sole dopant to form the PPy/RGD-ITO microelectrode.The surface topology morphology,wettability and composition of the resulted PPy/RGD composite film were characterized by atomic force microscope(AFM),contact angle measurement instrument and fourier transform infrared spectrometer(FTIR)respectively.The human lung cancer A549 cells spreading,adhesion and proliferation experiments were conducted to investigate the interaction between the PPy/RGD composite with cells.Used the PPy/RGD-ITO microelectrode as sensing electrode,A549 cells adhesion and proliferation,as well as the cytotoxicity of Polyphyllin I,a well-known natural anti-cancer molecule,were analyzed by electrochemical impedance spectroscopy.Resulted showed that the RGD molecule was doped into the PPy matrix successfully through the facile electrochemical copolymerization and the resulted PPy/RGD composite film has excellent surface physical properties.The RGD molecule doped into the PPy matrix retained its biology activity and promoted A549 cells spreading,adhesion and proliferation when compared with bare ITO electrode and poly(4-styrene sulfonate)(PSS)doped PPy film.Finally,as the morphological change of A549 cells on the surface of PPy/RGD-ITO microelectrode would change the impedance spectrum characteristics of the electrode system,the information about A549 cells during the process of adhesion and proliferation as well as the quantitative cytotoxicity of Polyphyllin I could be obtained by the electrochemical impedance technology.Therefore,the PPy/RGD film prepared by doping the RGD molecule into the PPy through the facile electrochemical copolymerization showed excellent biocompatibility.In future,the PPy/RGD film could be used as the coupling interface between electronic system and biological cell system and for researching the cellular bio-behaviors and drug screening.